hello all my amp is crackiling on one speaker. took out the amp and tried the other speaker in the back of the amp with the same crackling coming from both speakers. i am using my amp with 3 kt88 valves as one blow up when i got the amp. to be honest with you all i don't really like the sound i am getting from this amp. and i am also using the xiang sheng 728a preamp. with monitor audio gr20. it just when i turn up the amp i get loads of distortion could this be because i am only running 3 kt88 valves in the yaqin 100b amp. kind regards mr young

so is that why my amp is distorting when turned up mate. and the sound is not very good. should i not play the amp until i get the kt88 valve in. do the valves need to be matching or can i put 2 of a different valve makes but they are all kt88 valves cheers for your reply lee

Quote:

Originally Posted by Rodeodave

Never, under no circumstances, run that amp with an incomplete set of output tubes. Since it's Class B, doing so you are lacking one complete half cycle of the signal, thus the distortion.

Read up on how tube amplifiers, especially Class B, work (Google if you must).

Hi - you should not be playing the amp at all unless you have all the KT-88. As mentioned being class B, a pair of KT 88 will work 1 per half cylce and you lack amplification of 50% of the signal. Not sure what this is doing to your transformer.
It will be ideal to have the KT 88s matched.

ok thank you i have turned it of now. and i will leave it alone. do you think the preamp ziang sheng 728a is a good match for the yaqin 100b. or should i sell the amp. and are my monitor audio worth keeping gr20. these are the valves i have been offerd for the yaqin 100b 2 Genelex Gold Lion and 2 Svetlena winged C. thanks all ee